1. Field of the Invention
The invention in general relates to underwater vehicles, and particularly to a laminar flow vehicle having an improved bow or nose portion.
2. Description of the Prior Art
As an underwater vehicle travels through the water, frictional drag forces are present which tend to decrease the vehicle speed. From a hydrodynamic standpoint it is well known that the vehicle speed can significantly be increased by maintaining a laminar boundary layer over its surface by using one of various known boundary layer control techniques such as selective heating of the vehicle shell.
The underwater ambient environment contains particulate matter which if present on the vehicle shell or in the thin fluid boundary adjacent the shell will cause a premature transition from laminar to tubulent flow thus reducing vehicle speed and performance. Particulate matter is herein defined as any bounded material that exhibits fluid properties across the boundary such as air bubbles, solid particles, plankton, etc.
The disruptive effect of particulate induced breakdown can be virtually eliminated if the particles can be removed from the vicinity of the nose portion of the vehicle and breakdown prevented or at least delayed to a few feet further down the vehicle body. This premature breakdown due to particulate matter is overcome by the present invention.